opensim-development – Blame information for rev 1

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1 eva 1 /*
2 * Copyright (c) Contributors, http://opensimulator.org/
3 * See CONTRIBUTORS.TXT for a full list of copyright holders.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 * * Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of the OpenSimulator Project nor the
13 * names of its contributors may be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
17 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
20 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
23 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27  
28 using System;
29 using OpenSim.Region.Framework.Interfaces;
30  
31 namespace OpenSim.Region.Framework.Scenes
32 {
33 public static class TerrainUtil
34 {
35 public static double MetersToSphericalStrength(double size)
36 {
37 //return Math.Pow(2, size);
38 return (size + 1) * 1.35; // MCP: a more useful brush size range
39 }
40  
41 public static double SphericalFactor(double x, double y, double rx, double ry, double size)
42 {
43 return size * size - ((x - rx) * (x - rx) + (y - ry) * (y - ry));
44 }
45  
46 public static double GetBilinearInterpolate(double x, double y, ITerrainChannel map)
47 {
48 int w = map.Width;
49 int h = map.Height;
50  
51 if (x > w - 2.0)
52 x = w - 2.0;
53 if (y > h - 2.0)
54 y = h - 2.0;
55 if (x < 0.0)
56 x = 0.0;
57 if (y < 0.0)
58 y = 0.0;
59  
60 const int stepSize = 1;
61 double h00 = map[(int) x, (int) y];
62 double h10 = map[(int) x + stepSize, (int) y];
63 double h01 = map[(int) x, (int) y + stepSize];
64 double h11 = map[(int) x + stepSize, (int) y + stepSize];
65 double h1 = h00;
66 double h2 = h10;
67 double h3 = h01;
68 double h4 = h11;
69 double a00 = h1;
70 double a10 = h2 - h1;
71 double a01 = h3 - h1;
72 double a11 = h1 - h2 - h3 + h4;
73 double partialx = x - (int) x;
74 double partialz = y - (int) y;
75 double hi = a00 + (a10 * partialx) + (a01 * partialz) + (a11 * partialx * partialz);
76 return hi;
77 }
78  
79 private static double Noise(double x, double y)
80 {
81 int n = (int) x + (int) (y * 749);
82 n = (n << 13) ^ n;
83 return (1.0 - ((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0);
84 }
85  
86 private static double SmoothedNoise1(double x, double y)
87 {
88 double corners = (Noise(x - 1, y - 1) + Noise(x + 1, y - 1) + Noise(x - 1, y + 1) + Noise(x + 1, y + 1)) / 16;
89 double sides = (Noise(x - 1, y) + Noise(x + 1, y) + Noise(x, y - 1) + Noise(x, y + 1)) / 8;
90 double center = Noise(x, y) / 4;
91 return corners + sides + center;
92 }
93  
94 private static double Interpolate(double x, double y, double z)
95 {
96 return (x * (1.0 - z)) + (y * z);
97 }
98  
99 public static double InterpolatedNoise(double x, double y)
100 {
101 int integer_X = (int) (x);
102 double fractional_X = x - integer_X;
103  
104 int integer_Y = (int) y;
105 double fractional_Y = y - integer_Y;
106  
107 double v1 = SmoothedNoise1(integer_X, integer_Y);
108 double v2 = SmoothedNoise1(integer_X + 1, integer_Y);
109 double v3 = SmoothedNoise1(integer_X, integer_Y + 1);
110 double v4 = SmoothedNoise1(integer_X + 1, integer_Y + 1);
111  
112 double i1 = Interpolate(v1, v2, fractional_X);
113 double i2 = Interpolate(v3, v4, fractional_X);
114  
115 return Interpolate(i1, i2, fractional_Y);
116 }
117  
118 public static double PerlinNoise2D(double x, double y, int octaves, double persistence)
119 {
120 double total = 0.0;
121  
122 for (int i = 0; i < octaves; i++)
123 {
124 double frequency = Math.Pow(2, i);
125 double amplitude = Math.Pow(persistence, i);
126  
127 total += InterpolatedNoise(x * frequency, y * frequency) * amplitude;
128 }
129 return total;
130 }
131 }
132 }